Effect of molecular adsorption on the electronic structure of single walled carbon nanotubes

Abstract

The study of adsorption of various gaseous molecules on Carbon nanotubes (CNTs) are of great importance because of its vast applications in science and technology. Most of these applications are based on electronic and transport property changes as a result of adsorption. Single walled carbon nanotubes (SWCNT) based sensors have gained significant interest especially due to the modification of their electrical properties with adsorption of simple chemical species on the surface. Due to their high surface to volume ratio, they may be able to act as good sensors and also as gas storage materials. It has also been demonstrated experimentally that the electronic properties of SWNTs are very sensitive to the chemical environment. Conventional sensors which are widely used to detect gases are comprised of thin film metal oxides of tin oxide, zinc oxide or indium oxide. These sensors lack flexibility, suffer with poor response times and fails to operate at lower temperatures. Carbon nanotubes can act as a better alternative for these applications because of their unique morphology. The main principle involved in detecting various gases by CNTs is by monitoring the conductance change associated with the charge transfer between CNTs and the adsorbed gases.